Light-sensitive multilayer photographic material and process for making the same



Oct. 129, 1940. B. GAsPAR 2,219,988

LIGHT-SENSITIVE MULTILAYERQPHOTOGRAPHIC MATERIAL AND PROCESS FOR MAKING THE-SAME Filed p 0 s; 1938 m a m w p w WW r m w M. w a s P 5 u a l w a H HM E fl H nm gm QWM 1- m TTHTM Pym n F m D n W. m.

Zhwentor Patented Oct. 29, 1940 LIGHT-SENSITIVE MuL'rILAmn moro- GRAPHIC MATERIAL AND rnoonss ron.

MAKING-SHE SAME.

. Bla Gaspar, Hollywood, Calif.

Application December 3,

1938, Serial No. 243,888

In Great BrltainDecember 9, 1937 Claims.

Photographic multilayer materials for color photographic purposes are known in which some or all of the various light sensitive layers contain, priorto exposure, the dye necessary for the formation of the final image. After exposure of the light sensitive layers, they are converted into colored pictures by local removal of the dyestuff. If two or inore layers are arranged upon the same support, it is necessary to sensitize at least two of the layers for differently colored light in order to produce the desired color selection picture in each individual layer with light corresponding to the sensitivity.

According to the present invention at least one of the layers contains the image forming dyestuff in a concentration higher than that required at the most intensely colored points of the image. The surplus of 'dyestufi acts as a screening dye and either prevents the light to which the layeris not to be exposed from entering the layer or in other cases the surplus of dyestuif prevents the light to which the layer is to be exposed from reaching the bottom of the layer and from entering the next following layer.

After the exposure of the material the surplus of the image forming dye is removed by a bleaching process of the same kind as used for the local bleaching of the dyestuff at the points where a silver image has been produced by developing. The surplus of dyestuff, however, is to be removed in a uniform manner as distinguished from the image-like removal of the dyestufl at the points of the silver deposit corre-' sponding to the image.

In order to obtain this uniform removal of the surplus dyestufi the colored emulsion is exposed to a diffuse illumination of a certain intensity which corresponds to the surplus of dyestuff and the larger the amount of dyestulf, the 40 higher the. intensity of illumination. The uniform exposure occurs beforethe development of the material or even before the image-forming exposure of the layer. The use of a fogged emulsion has the same effect and the degree of, fog may be determined by tests so that it is sufficient for a decrease of the dyestuff concentration from its original value to that corresponding to the color intensity required at the most intensely colored parts of the final multicolor image. Insteadof a fogged emulsion, one containing a, corresponding amount of exposed and developed silver halide or colloidal silver may be used. It is furthermore possible to produce a uniform blackening of the layer or layers by a uniform illumination with light to which.

the layer is specifically sensitised, and several layers can simultaneously be illuminated with such light. ExampZa- -AS shown in the drawing a film is used comprising on one side of the support a blue-green emulsion sensitive to blue 5 and on the other side a yellow emulsion sensitised to red and amagenta dyed emulsion sensitised to blue. The dyestuffs used are:

G. per sq. m.

)flyenewalkgelb G is referred to in Schultz Farbstoiftabellen, Leipzig 1932, 7th edition, volume -2, page 232, and Tuchechtbrillantrot 2B in Schultz Farbstofftabellen 1.0., page 221.

If the yellow dyestufi were used in a concentration of 1.2 g. per sq. m. the blue printing light used for exposure of the outer layers would produce a slight printing effect on the surfaces of the yellow layer. According to the invention, the concentration of the yellow dye is raised to about 1.8 g, per sq. m. The yellow emulsion is either fogged or is illuminated to such an extent that during the treatment of the material by a 5 per cent acid thiocarbamide solution the yellow dyestuif is reduced to a concentration of about 1.2 g. The two other layers may also contain the dyestuffs in excess of that given above and all of the layers or those containing more dyestufi than required in the final image may be sensitised to infra-red light so that by onedifiuse illumination the quantity of silver may be produced which is necessary to 5 reduce .the dyestuff concentration to the required degree. In the above described example the yellow dyed layer may, for example, contain cryptocyanine as a. sensitizer for infra-red. After exposure and development the various silver im- 40 ages in the three layers are transformed into dye-images by 5% hydrobromic acid or acid thiocarbamide solutions.

What is claimed is: I

1. A light-sensitive multilayer photographic material comprising a support and a plurality of superposed silver halide emulsion layers, at

least one of the layers being dyed to a color density higher than that required at the most intensely colored points of the image by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of metallic silver, said layer containing an excess of uniformly distributed'silver in the form of colloidal silver, said excess amount of said silver corresponding to the surplus of dye 2. A light-sensitive multilayer photographic material comprising a support and a plurality of superposed silver'halide emulsion layers, at least one of the layers being dyed to a color density higher. than that required at the most intensely colored points of the image by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of metallic silver, said layer containing an excess of uniformly distributed silver in the form of uniformly exposed silver salt, said excess amount of said silver corresponding to the sur plus of dye. i

3. A light-sensitive multilayer photographic material comprising a support and a-plurality of superposed silver halide emulsion layers including at least two differentially sensitizedto predetermined spectral ranges, at least one of the lay- ,ers being dyed to a color density higher than that required at the most intensely colored points of the image by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of metallic silver, said layer containing an excess of uniformly distributed silver in the form of light-sensitive silver salt and a sensitizer for selective exposure of said silvert salt to a spectral range different from said predetermined spectral ranges, said excess amount of said silver corresponding .to the surplus of dye.

4. A light-sensitive multilayer photographic material comprising a support and a plurality of superposed silver halide emulsion layers, at least one of the layers being dyed to a color density materially higher than that required at the most intensely colored points of the image by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of metallic silver by a dye destroying agent, said layer containing an excess of uniformly distributed available silver, said excess amount of said available silver corresponding to the surplus of dye for uniformly'reducing the color density of said dyed layer to an amount substantially equal to that needed to reproduce the most intensely colored points of the image by said dye. l

5. A process for producing multicolor photographic images from a light-sensitive-multilayer photographic material comprising a support and a plurality of superposed silver halide emulsion layers, at least one of said silver halide emulsion layers being dyed to a color density materially higher than that required at the most intensely colored points of the image by a dye which is fast to ordinary photographic treating solutions but capable of being locally bleached in the presence of metallic silver by a dye destroying agent,

which comprises forming within said dyed emulsion layer a uniform deposit of metallic silver the amount of said uniformly distributed silver corresponding to the surplus of dye present within said layer, recording the difierent color selection pictures of the object each in the corresponding silver halide emulsion layer, developing and converting said records to dye images, the dye image within said pre-dyed layer being formed by the local destruction of the dye at the places where silver is present, and removing the metallic silver from the layers.

BE'LA GAsPAR. 

